Fix clippy::needless_borrow lint violations (#36444)

Release Notes:

- N/A

crates/markdown/src/markdown.rs

@@ -875,7 +875,7 @@ impl Element for MarkdownElement {
                                 (CodeBlockRenderer::Custom { render, .. }, _) => {
                                     let parent_container = render(
                                         kind,
-                                        &parsed_markdown,
+                                        parsed_markdown,
                                         range.clone(),
                                         metadata.clone(),
                                         window,

crates/markdown/src/parser.rs

@@ -247,7 +247,7 @@ pub fn parse_markdown(
                             events.push(event_for(
                                 text,
                                 range.source_range.start..range.source_range.start + prefix_len,
-                                &head,
+                                head,
                             ));
                             range.parsed = CowStr::Boxed(tail.into());
                             range.merged_range.start += prefix_len;